Expansion cards are typically inserted into expansion slots, such as on a motherboard of a computer system, for electrically connecting electronics on the expansion card and electronics on the motherboard. The expansion card adds functionality to the computer system via an expansion bus. For example, the expansion card provides and/or expands upon features not offered by the motherboard. Expansion cards often include various circuits, such as a charging circuit, which consume power provided via the electrical connection to the expansion slot.